ANCIENT AMERICAN LAKE— BRADLEY 281 



read only after learning how the symbols were formed and what rela- 

 tion each bore to modern language. So it is with the record left by 

 the ancient Lake Uinta. Geologists in the seventies of the last century 

 pried apart the stony pages and found that they contained a story 

 about an ancient lake. But the story could be read no faster than 

 the science of geology grew and provided the keys for mterpreting the 

 symbols. Moreover, the reading was slow because fragments of the 

 record came to light only piecemeal as exploring geologists penetrated 

 more and more deeply into those parts of the arid West away from 

 established routes of travel. And finally, long passages in the text 

 remained obscure until the study of modern lakes revealed what was 

 taking place in them, for the characteristics of an ancient lake can be 

 understood only by analogy with the lakes of today. Thus only 

 recently, as more and more parts of the story have been assembled 

 and integrated into an ordered sequence, has it been possible to learn 

 how complex and varied is the history of Lake Uinta. That history 

 includes a wealth of information, not only about the plant and animal 

 societies that dwelt in the lake itself and on the adjacent land, but 

 also about the ways in which they changed to meet a gradually chang- 

 ing environment. It tells how for thousands of years the lake kept a 

 sort of calendar, by depositing each year a thin layer of peculiar 

 sediment that was sharply marked off from the layers formed the 

 year before and the year after. Though these annual layers do not 

 continue through the whole record it has been possible from them to 

 estimate that Lake Uinta was in existence for millions of years. The 

 history is more than a recital of elapsed years, hov/ever, for it tells 

 both of major catastrophes and of such trivial incidents as the migra- 

 tion along the water's edge of a swarm of small, swollen-headed larvae 

 which, had fate been less harsh, would one day have split their skins 

 and emerged as adult gnats. From tliis emergence, however, they 

 were prevented by a drop in the lake level, which left them to perish 

 and dry in the sun untU the water rose again and deposited on their 

 remains a shroud which it fashioned out of minute interlocking 

 mineral particles. 



I 



In the beginning the site of Lake Uinta was a broad, nearly level 

 alluvial plain — a sort of huge amphitheater, bordered on three sides 

 by mountains but open to the south. Streams from the mountains 

 wound listlessly across the plain and rested in the grassy marshes. 

 But this landscape was destined to change, for, beneath the plain, 

 the stony shell of the earth was beginning with subtle slowness to 

 warp downward. Thereafter the streams spread broadly over the 

 meadows, changing them to lakes. At first there were two large lakes, 

 but as the downwarping continued these soon expanded and coalesced 



